The GPM Aluminium Outer Portal Drive Housing is manufactured for the Traxxas TRX4 Trail Crawler using 6061 T6 aluminium to deliver improved structural performance over stock plastic housings. This outer housing secures the inner gears within the knuckle arms to preserve gear alignment under torque and impact, while remaining compatible with the original plastic components. Precision machining and a 3D streamlined profile ensure repeatable fits and straightforward installation for advanced hobbyists and technicians.